This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A222321 #7 Jul 23 2025 02:29:17 %S A222321 1,0,4,52,674,38238,2284728,620488671,174162198742,206752746752932 %N A222321 Number of n X n 0..1 arrays with exactly floor(n X n/2) elements unequal to at least one king-move neighbor, with new values introduced in row major 0..1 order. %C A222321 Diagonal of A222328 %e A222321 Some solutions for n=4 %e A222321 ..0..0..0..0....0..1..0..0....0..0..0..0....0..0..1..0....0..0..0..1 %e A222321 ..1..0..0..0....1..0..0..0....0..0..0..0....1..1..1..1....0..0..0..1 %e A222321 ..1..0..0..0....0..0..0..0....0..0..0..1....1..1..1..1....0..0..0..1 %e A222321 ..0..0..0..0....0..0..0..0....0..0..1..1....1..1..1..1....0..0..0..1 %K A222321 nonn %O A222321 1,3 %A A222321 _R. H. Hardin_ Feb 15 2013